Net Loss Per Share - Numerators and Denominators of Basic and Diluted Net Income (Loss) Per Share Computations (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 28, 2019	Jun. 29, 2018	Jun. 28, 2019	Jun. 29, 2018
Numerator:
Net loss	$ (11,845)	$ (2,913)	$ (23,151)	$ (16,607)
Denominator:
Basic and diluted	88,931	85,304	88,554	84,616
Net loss per share:
Basic and diluted	$ (0.13)	$ (0.03)	$ (0.26)	$ (0.20)